Eight nematode species of the order Monhysterida are described from the East Flower Garden at 72 m depth in the north-western Gulf of Mexico. The material is from sandy and rocky bottom samples influenced or beyond the influence o f a sulphide-rich brine seep. Seven species are new to science: Monhystera anoxybiotica sp.n., Gonionchus intermedius sp.n., Theristus (Theristus) coplatus sp.n., Theristus (Theristus) rezaki sp.n., Xyala oxybiotica spa., Desmolaimoides thiobioticus gen. et sp.n. and Linhomoeus gittingsi sp.n. Specimens of a Linhomoeus species are also described. The species is probably new to science, but the available material only includes females and juveniles.